This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Time is requested to perform a 10.5 [unreadable]s all atom simulation of the 43E1 hemichannel embedded in an explicit POPC membrane and solvent system with a large applied electric field to explore the conformational path made by the channel as it transits from the open to closed state in response to voltage. The basic strategy of our simulation is to increase the applied potential and/or system temperature in 1 [unreadable]s increments while monitoring the trajectories of voltage-dependent (charge interactions) and voltage-independent (hydrophobic interactions) properties that are directly related to stability of the open channel and must change with channel closure. The conformations of the channel pore in the open and closed states have been determined experimentally and provide a means of validating the end point of the simulation.